DESCRIPTION: Accurate estimation of the number and characteristics of hard drug abusers and operatives has long plagued policy makers and treatment providers. Hard drug users are under-represented in national, state, and local surveys. The goal of the proposed research is to refine a survey methodology that can accurately estimate the size of the "hard-to-reach," hidden population of hard drug users who have used heroin, cocaine, and crack within the last 30 days, and of operatives in the drug trade (e.g. sellers, go-betweens, and managers of shared consumption locales). The proposed statistical survey builds upon several strengths at National Development and Research Institutes (NDRI) to accomplish the following objectives: A) to refine and implement strategies for estimating, within a delimited geographical area, the number of current users and operatives; B) to develop and evaluate recruitment strategies for accessing hard drug users and operatives within formal sampling designs in multiple neighborhoods in the New York region; C) to systematically obtain self-reports of specific drug(s) used, frequencies of use, needle and drug sharing, contacts with institutions, and other factors related to drug use, and to obtain urine and hair specimens, D) to document and compare the concordance of the respondent's self-reports of drug use and HIV/AIDS status with biological testing for drugs of abuse and HIV. In previous and current studies conducted by Drs. Johnson, Friedman, and other investigators, and AIDS outreach programs nationally, ethnographic outreach techniques have been developed to locate specific subpopulations of hard drug users and operatives and recruit them for in-depth interviews. Ethnographic random sampling will be conducted in East Harlem (substudy 1). Project staff will conduct blockface 'counts of operatives, define strata and select grids and blockfaces, recruit and select operatives and hard drug users, conduct computerized interviews, obtain urine and hair samples, and statistically estimate the number of hard drug users and operatives. Staff would modify and implement these strategies during other interrelated substudies in other New York communities with many operatives and with few operatives. The success in employing the specific outreach methods, blockface enumeration strategies, enrollment of operatives, recruitment techniques for gaining interviews with operatives and their customers, and careful statistical estimation of hard drug users and operatives in these localities will be provided in several project reports.